Thermal liquid heater



1961 G. STABENOW 2,994,308

THERMAL LIQUID HEATER Filed Sept. 16, 1959 4 Sheets-Sheet 1 A TTORNEYS.

1961 G. STABENOW 2,994,308

THERMAL LIQUID HEATER Filed Sept. 16, 1959 4 Sheets-Sheet 2 IN V EN TOR. fie01y8iabe110m A TTORNEYS.

9 G. STABENOW 2,994,308

THERMAL LIQUID HEATER Filed Sept. 16, 1959 4 Sheets-Shet 5 IN V EN TOR. B 62mg Siafimm;

A TTORNEYS.

Aug. 1, 1961 G. STABENOW 2,994,303

THERMAL LIQUID HEATER Filed Sept. 16, 1959 4 Sheets-Sheet 4 1 INVENTOR.

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ATTORNEYS.

United States Patent Ofice Patented Aug. 1, 1961 2,994,308 THERMAL LIQUID HEATER Georg Stabenow, East Stroudsburg, Pa., assignor to La Mont Steam Generators, Inc., New York, N.Y., a corporation of Delaware Filed Sept. 16, 1959, Ser. No. 840,386 7 Claims. (Cl. 122-406) This invention relates to boilers and other thermal liquid heaters and in particular to heaters of the type in which fluid is circulated through tubes provided for that purpose which are subjected to flame discharged from a burner.

It is a principal object of this invention to provide a thermal liquid heater of the above type which reduces to a minimum the number of vertical flow circuits.

It is also an object of this invention to provide a thermal liquid heater of the above type with a minimum number of tube holes and plugs thereby reducing construction costs.

It is a further object of this invention to provide a hot water generator of the above type which reduces to a minimum the number of intermediate headers required.

In describing the preferred embodiment of the invention illustrated in the drawings specific terminology will be resorted to for the sake of clarity. However, it is not the intention to be limited tothe specific terms so selected. Other objects and advantages will be apparent from the following description and the drawings of which:

FIG. 1 is a side elevation partly in cross section of a thermal liquid heater constructed in accordance with the invention;

FIG. 2 is a plan view partially broken away of the structure of FIG. 1 with the fuel heating apparatus eliminated;

FIG. 3 is a front elevation partly broken away and partly in cross section of the structure of FIG. 1;

FIG. 4 is a perspective schematic diagram illustrating the fluid circuits in the thermal liquid heater of FIG. 1;

FIG. 5 is a cross sectional view along the line V-V of FIG. 2 showing the orifice structure used in the invention.

.The thermal liquid heater of this invention comprises a housing based upon a floor 11 of concrete or other suitable foundation material. Fuel is burned in burner 12 and is power-driven through opening 13 into the interior of housing 10 by means of blower 14. Within the housing 10 the products of combustion pass over front baffle .15 under rear baffle 16 and thence out of housing 10 through flue 17. Housing 10 is made up of front wall 18, back wall 19, roof 20, base 21 and side walls 22 and 23. The main fluid intake header 30 is positioned at the upper rear portion of housing 10 along back wall 19 and is connected to a plurality of fluid carrying tubes arranged in bank 31 below flue 17. Bank 31 extends from the upper portion of housing 10 to a point close to the bottom thereof and connects through back wall 19 to first intermediate header 33 which is disposed along the bottom of rear wall 19 and extends a short distance along side walls 22 and 23. Header 33 is there connected to a plurality of tubes forming lower side banks 35 and 36 respectively. The tubes of side banks 35 and 36 rise from header 33 in a vertical direction to a point just beneath bank 31 and thence forward at an angle of 90 horizontally along side walls 23 and 22 respectively. At front wall 18 banks 35 and 36 again turn 90 and pass vertically sufliciently far to enable the tubes to reverse direction in the same vertical plane as illustrated partly in FIG. 4. Banks 35 and 36 then proceed rearwardly parallel to side walls 23 and 22 respectviely to rear bafile 16. At rear baflie 16 banks 35 and 36 pass through two 90-degree turns in a plane parallel to rear bafile 16 and then return in a forward direction to front wall 18 along side walls 23 and 22 respectively. At front wall 18 banks 35 and 36 extend toward each other and then reverse forming a double tube layer along the upper portion of front wall 18 and then connect into opposite ends of front intermediate header 40. Front intermediate header 40 is a U-shaped tube extending along the outside of front wall 18 along the lower portion thereof and extending vertically along the sides of front wall 18 to a point near the top thereof. Along the lower horizontal portion of header 40 are connected a plurality of parallel tubes forming floor bank 41 which extends rearwardly to front baffle 15. There the tubes extend vertically at 90 forming vertical bank 42 along the front face of front baffle '15 and then rearwardly diagonally from the top of front baflle 15 to the juncture of rear baffle 16 with roof 20.. The tubes then form bridge bank 43 which extends forwardly beneath roof 20 to front wall 18 and thence into outlet header 44 which delivers the heated fluid from theboiler.

The fluid to be heated enters inlet header 30 and passes: downwardly throguh bank 31 into header 33. Fromheader 33 the fluid enters sidebanks 35 and 36 and passes to the front of the generator, then rearward to rear baffle 16 across the face of rear baflie *16 and forward to front intermediate header 40. Header 40 carries the fluid to the floor of housing 10 where it enters bank 41 which: carries it rearward to front baffle 15 vertically along bank 42 and thence to the roof 20 of housing 10. It moves forwardly through bank 43 to outlet header 44.

By virtue of the tube arrangement described above the fluid to be heated is first exposed to the products of combustion just below flue 17 where they leave housing 10. The flow of fluid is generally counter to the passage of the heating gases in bank 31. From header 33 the fluid is separated to flow in two parallel circuits disposed along the side walls 22 and 23 of housing 10. Here the flow of fluid is alternately the same as and counter to the flow of the heating gases. Included in this arrangement is the disposition of the tubes along the front face of rear baffle 16 which exposes the fluid in the tubes to the direct ac tion of the heating gases passing over front baflle 1S and under rear baflle '16. From front intermediate header '40 the fluid passes along the floor of housing 10 and upward along the face of front bafile 15 to the roof 20 of housing 10 and is there directly exposed to the initial entry of heating gases. The final passage of fluid in housing 10 is along the roof 20 where the final heating is achieved.

It will thus be seen that by virtue of the novel arrangement of tubes, the fluid to be heated is progressively exposed to higher temperatures of the pro-ducts of combustion thereby providing a more uniform heating of the fluid with less danger of overheating of the tubes. The virtual elimination of intermediate headers serves further to reduce potential hot spots in the tubes and greatly reduces the costs of construction.

The thermal liquid heater provided by the invention is designed to function with liquid circuits and is not adapted for efficient use with vapor circuits. The generator thus constructed is eflicient in design both in terms of conboiler tubes 36. The orifice structure is shown in FIG. 5 with particular reference to an orifice inserted in header 33 and tubes 35. The boiler tube is inserted in the header and is provided with a flattened end to secure it there. A strainer tube 24 is inserted in the inner end of tube 35 and strainer 24 and tube 35 are provided with complementary flared and tapered portions to provide suitable alignment and engagement. The end of strainer tube 24 remote from boiler tube 35 is maintained in place by retainer plug 29 which extends from header plug 28 which is threadably inserted in header 43. Orifice plate 25 having an opening 26 is inserted in the end of strainer tube 24. The heated fluid passes through the opening 26.

The size of the opening 26 is related in a predetermined manner to the rate of flow of fluid through the boiler tubes and the potential drop or fluid head between headers such as header 33 and header so that the pressure drop of the fluid flowing through the opening 26 is greater than the head of fluid between the two headers. The particular purpose is to prevent vaporization which could block the flow of fluid through the boiler tubes. If, for example, vaporization should occur in a single tube of the series of boiler tubes 35, the pressure effect of the hydraulic head of the tube would be at least partially lost but with the orifice present its pressure drop would still be more than equivalent to the fluid heads of the other tubes of the series. Thus, there is positive assurance that there will always be a greater pressure at the intake portion of the tube than the back pressure due to the heights of the fluid columns of the other tubes of the series even when vaporization has started to take place in a single tube.

Accordingly, it will be appreciated that notwithstanding the fact that the recirculated liquid has already been heated in the convection portion 61, it does not vaporize in the combustion section in a manner to impede the flow of liquid. The hot liquid in the combustion section is apportioned by the orifices in header 33. The words apportioning and apportionment are not intended to imply a distribution in exactly equal proportions since the relative quantities of flow' may vary somewhat from tube to tube and from time to time. However, when the flow in any given tube tends to stop or slow down greatly with respect to the flow in the other tubes, the operation of the orifices tends to increase the rate of flow into that tube with respect to the rate of flow into the other tubes of the series and the foregoing words are intended to apply to such relative increase. Even intense heat directed on a relatively small area of the boiler tubes is insufficient to impede the flow of liquid enough to damage the tube.

While the use of orifices is particularly desirable where there is downflow in the combustion section of the heater, they are also extremely useful in providing balanced flow between headers in boiler tubes having upflow and horizontal flow as in the present case. The orifices insure balanced flow among the several boiler tubes providing greater efficiency and preventing the creation of hot spots.

While in accordance with the provision of the statutes, 1 have illustrated and described the best form of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form described Without departing from the spirit and scope of the invention, as set forth in the appended claims, and that in some cases certain. features of my invention may be used to advantage without a corresponding use of other features.

What I claim is:

l. A thermal liquid heater comprising a housing having a roof, fioor, frontand back walls and side Walls, heating means disposed in the front wall of. said. housing.'flue means for emitting the products of said heating means disposed in the roof of said housing near the back wall thereof, rear baffle means transversely disposed across the width of said housing and depending from the roof thereof to a point spaced from the bottom thereof, said rear'baflie means being spaced from said rear Wall, front baflie means transversely disposed across the width of said housing extending upwardly from the floor thereof to a point spaced from the roof thereof, said front baflie means being spaced from said rear balfle means, first fluid-carrying tube means disposed between the rear wall of said housing and said rear baffle means and extending from a point near the flue means downwardly to about the bottom of said .rear bafiie means, said first fluid-carrying tube means being arranged for exposure to the coolest part of the products of said heating means, second fluid-carrying tube means disposed along the lower portions of the side walls of said housing and extending to substantially cover the front face of said rear bafiie means and further extended to cover the upper portion of the inside of the front wall of said housing, said second fluid-carrying tube means being arranged for intermediate exposure to the products of said heating means, third fluid-carrying tube means extended along the floor of said housing from the front wall thereof upwardly along the front face of said front baffle means to the top thereof, then upwardly and rearwardly toward the roof of said housing means and forwardly along and adjacent to the roof of said housing to the front wall thereof, said third fluid-carrying tube means being arranged for exposure to the hottest part of the products of said heating means, said first and second fluid-carrying tube meansbeing connected by fluid-carrying first header means and said Seeand and third fluid-carrying tube means being connected by fluid carrying second header means.

2. The thermal liquid heater of claim 1 wherein the headers are all disposed outside of said housing.

3. The thermal liquid heater of claim 1 wherein said first fluid-carrying tube means comprises a plurality of parallel tubes folded upon themselves and extending alternately forward and rearward of said housing.

4. The thermal liquid heater of claim 1 wherein said second fluid-carrying tube means comprises two symmetrical banks of tubes arranged in parallel, said banks of. tubes extending first upwardly of said housing then upwardly at the front wall thereof and rearwardly of said rear baflie means and thence at right angles to said side walls in a plane parallel to said rear bafiie means thence through two right angle bends across the front face of said rear baffie means and forwardly along the side walls of said housing to the front wall thereof where they are looped toward the middle of the front of said housing and thence out through said header means.

5. The thermal liquid heater of claim 1 wherein said fluid-carrying tube means comprises pluralities of tubes arranged in parallel and wherein said banks of tubes are arranged in series.

6. The thermal liquid heater of claim 1 wherein the said second fluid-carrying tube means have restrictive orifice means at the connection between said first fluidcarrying tube means and said first header means, said orifice means having an opening which is of less area than the area of the corresponding tube and which has an area providing a pressure drop which is greater than the pressure drop of the entire length of the boiler tube in which it is located.

7. The thermal liquid heater of claim 6, wherein said restrictive orifices are arranged for the draining of said heater without inversion of the liquid circuits thereof.

References Cited in the file of this patent UNITED STATES PATENTS 2,823,651 Marshall Feb. 18, 1958 2,860,612 Durham NOV. 18, 1958 FOREIGN PATENTS V 636,769 Great Britain May 3, 1950 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No; 2,994,308 August l 1961 Georg Stabenow It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent. should read as "corrected below.

Column 2 line 23, for "throguh" read through 5 column 4, line 44, for "of" read to Signed and sealed this 5th day of December 1961.-

(SEAL) Attest:

ERNEST W. SWIDER I DAVID L. LADD Attesting Officer Commissioner of Patents USCOMM-DC- 

